The invention relates to a method for operating a motor vehicle.
In order to increase theft prevention in modern motor vehicles, electronic immobilizers are a legal requirement. Such immobilizers comprise a portable part, for example a vehicle key, in which a piece of cryptographic information is stored and can be transmitted to further electronic components of the motor vehicle by a transponder, for example. One of these further components, usually an engine controller, stores a further piece of cryptographic information. Only if the piece of information transmitted by the portable component is compatible with the piece of information stored in the motor vehicle is it possible to start the motor vehicle.
Such immobilizers can be overcome by changing the engine controller and replacing it with a new one that is compatible with a key having prescribed cryptographic information.
In order to provide improved security, DE 10 2010 044 722 A1 proposes the use of a piece of physically coded cryptographic information in the vehicle. By way of example, this is accomplished by casting metal particles in a stochastic distribution in plastic and measuring a physical property, which is dependent on the distribution of the metal particles, and using this measured value as cryptographic information. In order to prevent simple bypassing, the sensor measured value is encrypted by a communication key in this process.
Such immobilizers are also susceptible to physical access, however, since the relevant controllers are relatively easy to change.